1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * uprobes-based tracing events 4 * 5 * Copyright (C) IBM Corporation, 2010-2012 6 * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com> 7 */ 8 #define pr_fmt(fmt) "trace_uprobe: " fmt 9 10 #include <linux/ctype.h> 11 #include <linux/module.h> 12 #include <linux/uaccess.h> 13 #include <linux/uprobes.h> 14 #include <linux/namei.h> 15 #include <linux/string.h> 16 #include <linux/rculist.h> 17 18 #include "trace_dynevent.h" 19 #include "trace_probe.h" 20 #include "trace_probe_tmpl.h" 21 22 #define UPROBE_EVENT_SYSTEM "uprobes" 23 24 struct uprobe_trace_entry_head { 25 struct trace_entry ent; 26 unsigned long vaddr[]; 27 }; 28 29 #define SIZEOF_TRACE_ENTRY(is_return) \ 30 (sizeof(struct uprobe_trace_entry_head) + \ 31 sizeof(unsigned long) * (is_return ? 2 : 1)) 32 33 #define DATAOF_TRACE_ENTRY(entry, is_return) \ 34 ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return)) 35 36 struct trace_uprobe_filter { 37 rwlock_t rwlock; 38 int nr_systemwide; 39 struct list_head perf_events; 40 }; 41 42 static int trace_uprobe_create(int argc, const char **argv); 43 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev); 44 static int trace_uprobe_release(struct dyn_event *ev); 45 static bool trace_uprobe_is_busy(struct dyn_event *ev); 46 static bool trace_uprobe_match(const char *system, const char *event, 47 struct dyn_event *ev); 48 49 static struct dyn_event_operations trace_uprobe_ops = { 50 .create = trace_uprobe_create, 51 .show = trace_uprobe_show, 52 .is_busy = trace_uprobe_is_busy, 53 .free = trace_uprobe_release, 54 .match = trace_uprobe_match, 55 }; 56 57 /* 58 * uprobe event core functions 59 */ 60 struct trace_uprobe { 61 struct dyn_event devent; 62 struct trace_uprobe_filter filter; 63 struct uprobe_consumer consumer; 64 struct path path; 65 struct inode *inode; 66 char *filename; 67 unsigned long offset; 68 unsigned long ref_ctr_offset; 69 unsigned long nhit; 70 struct trace_probe tp; 71 }; 72 73 static bool is_trace_uprobe(struct dyn_event *ev) 74 { 75 return ev->ops == &trace_uprobe_ops; 76 } 77 78 static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev) 79 { 80 return container_of(ev, struct trace_uprobe, devent); 81 } 82 83 /** 84 * for_each_trace_uprobe - iterate over the trace_uprobe list 85 * @pos: the struct trace_uprobe * for each entry 86 * @dpos: the struct dyn_event * to use as a loop cursor 87 */ 88 #define for_each_trace_uprobe(pos, dpos) \ 89 for_each_dyn_event(dpos) \ 90 if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos))) 91 92 #define SIZEOF_TRACE_UPROBE(n) \ 93 (offsetof(struct trace_uprobe, tp.args) + \ 94 (sizeof(struct probe_arg) * (n))) 95 96 static int register_uprobe_event(struct trace_uprobe *tu); 97 static int unregister_uprobe_event(struct trace_uprobe *tu); 98 99 struct uprobe_dispatch_data { 100 struct trace_uprobe *tu; 101 unsigned long bp_addr; 102 }; 103 104 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); 105 static int uretprobe_dispatcher(struct uprobe_consumer *con, 106 unsigned long func, struct pt_regs *regs); 107 108 #ifdef CONFIG_STACK_GROWSUP 109 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 110 { 111 return addr - (n * sizeof(long)); 112 } 113 #else 114 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 115 { 116 return addr + (n * sizeof(long)); 117 } 118 #endif 119 120 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) 121 { 122 unsigned long ret; 123 unsigned long addr = user_stack_pointer(regs); 124 125 addr = adjust_stack_addr(addr, n); 126 127 if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret))) 128 return 0; 129 130 return ret; 131 } 132 133 /* 134 * Uprobes-specific fetch functions 135 */ 136 static nokprobe_inline int 137 probe_mem_read(void *dest, void *src, size_t size) 138 { 139 void __user *vaddr = (void __force __user *)src; 140 141 return copy_from_user(dest, vaddr, size) ? -EFAULT : 0; 142 } 143 /* 144 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max 145 * length and relative data location. 146 */ 147 static nokprobe_inline int 148 fetch_store_string(unsigned long addr, void *dest, void *base) 149 { 150 long ret; 151 u32 loc = *(u32 *)dest; 152 int maxlen = get_loc_len(loc); 153 u8 *dst = get_loc_data(dest, base); 154 void __user *src = (void __force __user *) addr; 155 156 if (unlikely(!maxlen)) 157 return -ENOMEM; 158 159 ret = strncpy_from_user(dst, src, maxlen); 160 if (ret >= 0) { 161 if (ret == maxlen) 162 dst[ret - 1] = '\0'; 163 else 164 /* 165 * Include the terminating null byte. In this case it 166 * was copied by strncpy_from_user but not accounted 167 * for in ret. 168 */ 169 ret++; 170 *(u32 *)dest = make_data_loc(ret, (void *)dst - base); 171 } 172 173 return ret; 174 } 175 176 /* Return the length of string -- including null terminal byte */ 177 static nokprobe_inline int 178 fetch_store_strlen(unsigned long addr) 179 { 180 int len; 181 void __user *vaddr = (void __force __user *) addr; 182 183 len = strnlen_user(vaddr, MAX_STRING_SIZE); 184 185 return (len > MAX_STRING_SIZE) ? 0 : len; 186 } 187 188 static unsigned long translate_user_vaddr(unsigned long file_offset) 189 { 190 unsigned long base_addr; 191 struct uprobe_dispatch_data *udd; 192 193 udd = (void *) current->utask->vaddr; 194 195 base_addr = udd->bp_addr - udd->tu->offset; 196 return base_addr + file_offset; 197 } 198 199 /* Note that we don't verify it, since the code does not come from user space */ 200 static int 201 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 202 void *base) 203 { 204 unsigned long val; 205 206 /* 1st stage: get value from context */ 207 switch (code->op) { 208 case FETCH_OP_REG: 209 val = regs_get_register(regs, code->param); 210 break; 211 case FETCH_OP_STACK: 212 val = get_user_stack_nth(regs, code->param); 213 break; 214 case FETCH_OP_STACKP: 215 val = user_stack_pointer(regs); 216 break; 217 case FETCH_OP_RETVAL: 218 val = regs_return_value(regs); 219 break; 220 case FETCH_OP_IMM: 221 val = code->immediate; 222 break; 223 case FETCH_OP_FOFFS: 224 val = translate_user_vaddr(code->immediate); 225 break; 226 default: 227 return -EILSEQ; 228 } 229 code++; 230 231 return process_fetch_insn_bottom(code, val, dest, base); 232 } 233 NOKPROBE_SYMBOL(process_fetch_insn) 234 235 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) 236 { 237 rwlock_init(&filter->rwlock); 238 filter->nr_systemwide = 0; 239 INIT_LIST_HEAD(&filter->perf_events); 240 } 241 242 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) 243 { 244 return !filter->nr_systemwide && list_empty(&filter->perf_events); 245 } 246 247 static inline bool is_ret_probe(struct trace_uprobe *tu) 248 { 249 return tu->consumer.ret_handler != NULL; 250 } 251 252 static bool trace_uprobe_is_busy(struct dyn_event *ev) 253 { 254 struct trace_uprobe *tu = to_trace_uprobe(ev); 255 256 return trace_probe_is_enabled(&tu->tp); 257 } 258 259 static bool trace_uprobe_match(const char *system, const char *event, 260 struct dyn_event *ev) 261 { 262 struct trace_uprobe *tu = to_trace_uprobe(ev); 263 264 return strcmp(trace_event_name(&tu->tp.call), event) == 0 && 265 (!system || strcmp(tu->tp.call.class->system, system) == 0); 266 } 267 268 /* 269 * Allocate new trace_uprobe and initialize it (including uprobes). 270 */ 271 static struct trace_uprobe * 272 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) 273 { 274 struct trace_uprobe *tu; 275 276 if (!event || !group) 277 return ERR_PTR(-EINVAL); 278 279 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); 280 if (!tu) 281 return ERR_PTR(-ENOMEM); 282 283 tu->tp.call.class = &tu->tp.class; 284 tu->tp.call.name = kstrdup(event, GFP_KERNEL); 285 if (!tu->tp.call.name) 286 goto error; 287 288 tu->tp.class.system = kstrdup(group, GFP_KERNEL); 289 if (!tu->tp.class.system) 290 goto error; 291 292 dyn_event_init(&tu->devent, &trace_uprobe_ops); 293 INIT_LIST_HEAD(&tu->tp.files); 294 tu->consumer.handler = uprobe_dispatcher; 295 if (is_ret) 296 tu->consumer.ret_handler = uretprobe_dispatcher; 297 init_trace_uprobe_filter(&tu->filter); 298 return tu; 299 300 error: 301 kfree(tu->tp.call.name); 302 kfree(tu); 303 304 return ERR_PTR(-ENOMEM); 305 } 306 307 static void free_trace_uprobe(struct trace_uprobe *tu) 308 { 309 int i; 310 311 if (!tu) 312 return; 313 314 for (i = 0; i < tu->tp.nr_args; i++) 315 traceprobe_free_probe_arg(&tu->tp.args[i]); 316 317 path_put(&tu->path); 318 kfree(tu->tp.call.class->system); 319 kfree(tu->tp.call.name); 320 kfree(tu->filename); 321 kfree(tu); 322 } 323 324 static struct trace_uprobe *find_probe_event(const char *event, const char *group) 325 { 326 struct dyn_event *pos; 327 struct trace_uprobe *tu; 328 329 for_each_trace_uprobe(tu, pos) 330 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 && 331 strcmp(tu->tp.call.class->system, group) == 0) 332 return tu; 333 334 return NULL; 335 } 336 337 /* Unregister a trace_uprobe and probe_event */ 338 static int unregister_trace_uprobe(struct trace_uprobe *tu) 339 { 340 int ret; 341 342 ret = unregister_uprobe_event(tu); 343 if (ret) 344 return ret; 345 346 dyn_event_remove(&tu->devent); 347 free_trace_uprobe(tu); 348 return 0; 349 } 350 351 /* 352 * Uprobe with multiple reference counter is not allowed. i.e. 353 * If inode and offset matches, reference counter offset *must* 354 * match as well. Though, there is one exception: If user is 355 * replacing old trace_uprobe with new one(same group/event), 356 * then we allow same uprobe with new reference counter as far 357 * as the new one does not conflict with any other existing 358 * ones. 359 */ 360 static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new) 361 { 362 struct dyn_event *pos; 363 struct trace_uprobe *tmp, *old = NULL; 364 struct inode *new_inode = d_real_inode(new->path.dentry); 365 366 old = find_probe_event(trace_event_name(&new->tp.call), 367 new->tp.call.class->system); 368 369 for_each_trace_uprobe(tmp, pos) { 370 if ((old ? old != tmp : true) && 371 new_inode == d_real_inode(tmp->path.dentry) && 372 new->offset == tmp->offset && 373 new->ref_ctr_offset != tmp->ref_ctr_offset) { 374 pr_warn("Reference counter offset mismatch."); 375 return ERR_PTR(-EINVAL); 376 } 377 } 378 return old; 379 } 380 381 /* Register a trace_uprobe and probe_event */ 382 static int register_trace_uprobe(struct trace_uprobe *tu) 383 { 384 struct trace_uprobe *old_tu; 385 int ret; 386 387 mutex_lock(&event_mutex); 388 389 /* register as an event */ 390 old_tu = find_old_trace_uprobe(tu); 391 if (IS_ERR(old_tu)) { 392 ret = PTR_ERR(old_tu); 393 goto end; 394 } 395 396 if (old_tu) { 397 /* delete old event */ 398 ret = unregister_trace_uprobe(old_tu); 399 if (ret) 400 goto end; 401 } 402 403 ret = register_uprobe_event(tu); 404 if (ret) { 405 pr_warn("Failed to register probe event(%d)\n", ret); 406 goto end; 407 } 408 409 dyn_event_add(&tu->devent); 410 411 end: 412 mutex_unlock(&event_mutex); 413 414 return ret; 415 } 416 417 /* 418 * Argument syntax: 419 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] 420 * 421 * - Remove uprobe: -:[GRP/]EVENT 422 */ 423 static int trace_uprobe_create(int argc, const char **argv) 424 { 425 struct trace_uprobe *tu; 426 const char *event = NULL, *group = UPROBE_EVENT_SYSTEM; 427 char *arg, *filename, *rctr, *rctr_end, *tmp; 428 char buf[MAX_EVENT_NAME_LEN]; 429 struct path path; 430 unsigned long offset, ref_ctr_offset; 431 bool is_return = false; 432 int i, ret; 433 434 ret = 0; 435 ref_ctr_offset = 0; 436 437 /* argc must be >= 1 */ 438 if (argv[0][0] == 'r') 439 is_return = true; 440 else if (argv[0][0] != 'p' || argc < 2) 441 return -ECANCELED; 442 443 if (argv[0][1] == ':') 444 event = &argv[0][2]; 445 446 if (!strchr(argv[1], '/')) 447 return -ECANCELED; 448 449 filename = kstrdup(argv[1], GFP_KERNEL); 450 if (!filename) 451 return -ENOMEM; 452 453 /* Find the last occurrence, in case the path contains ':' too. */ 454 arg = strrchr(filename, ':'); 455 if (!arg || !isdigit(arg[1])) { 456 kfree(filename); 457 return -ECANCELED; 458 } 459 460 *arg++ = '\0'; 461 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 462 if (ret) { 463 kfree(filename); 464 return ret; 465 } 466 if (!d_is_reg(path.dentry)) { 467 ret = -EINVAL; 468 goto fail_address_parse; 469 } 470 471 /* Parse reference counter offset if specified. */ 472 rctr = strchr(arg, '('); 473 if (rctr) { 474 rctr_end = strchr(rctr, ')'); 475 if (rctr > rctr_end || *(rctr_end + 1) != 0) { 476 ret = -EINVAL; 477 pr_info("Invalid reference counter offset.\n"); 478 goto fail_address_parse; 479 } 480 481 *rctr++ = '\0'; 482 *rctr_end = '\0'; 483 ret = kstrtoul(rctr, 0, &ref_ctr_offset); 484 if (ret) { 485 pr_info("Invalid reference counter offset.\n"); 486 goto fail_address_parse; 487 } 488 } 489 490 /* Parse uprobe offset. */ 491 ret = kstrtoul(arg, 0, &offset); 492 if (ret) 493 goto fail_address_parse; 494 495 argc -= 2; 496 argv += 2; 497 498 /* setup a probe */ 499 if (event) { 500 ret = traceprobe_parse_event_name(&event, &group, buf); 501 if (ret) 502 goto fail_address_parse; 503 } else { 504 char *tail; 505 char *ptr; 506 507 tail = kstrdup(kbasename(filename), GFP_KERNEL); 508 if (!tail) { 509 ret = -ENOMEM; 510 goto fail_address_parse; 511 } 512 513 ptr = strpbrk(tail, ".-_"); 514 if (ptr) 515 *ptr = '\0'; 516 517 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); 518 event = buf; 519 kfree(tail); 520 } 521 522 tu = alloc_trace_uprobe(group, event, argc, is_return); 523 if (IS_ERR(tu)) { 524 ret = PTR_ERR(tu); 525 /* This must return -ENOMEM otherwise there is a bug */ 526 WARN_ON_ONCE(ret != -ENOMEM); 527 goto fail_address_parse; 528 } 529 tu->offset = offset; 530 tu->ref_ctr_offset = ref_ctr_offset; 531 tu->path = path; 532 tu->filename = filename; 533 534 /* parse arguments */ 535 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 536 tmp = kstrdup(argv[i], GFP_KERNEL); 537 if (!tmp) { 538 ret = -ENOMEM; 539 goto error; 540 } 541 542 ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp, 543 is_return ? TPARG_FL_RETURN : 0); 544 kfree(tmp); 545 if (ret) 546 goto error; 547 } 548 549 ret = register_trace_uprobe(tu); 550 if (ret) 551 goto error; 552 return 0; 553 554 error: 555 free_trace_uprobe(tu); 556 return ret; 557 558 fail_address_parse: 559 path_put(&path); 560 kfree(filename); 561 562 pr_info("Failed to parse address or file.\n"); 563 564 return ret; 565 } 566 567 static int create_or_delete_trace_uprobe(int argc, char **argv) 568 { 569 int ret; 570 571 if (argv[0][0] == '-') 572 return dyn_event_release(argc, argv, &trace_uprobe_ops); 573 574 ret = trace_uprobe_create(argc, (const char **)argv); 575 return ret == -ECANCELED ? -EINVAL : ret; 576 } 577 578 static int trace_uprobe_release(struct dyn_event *ev) 579 { 580 struct trace_uprobe *tu = to_trace_uprobe(ev); 581 582 return unregister_trace_uprobe(tu); 583 } 584 585 /* Probes listing interfaces */ 586 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev) 587 { 588 struct trace_uprobe *tu = to_trace_uprobe(ev); 589 char c = is_ret_probe(tu) ? 'r' : 'p'; 590 int i; 591 592 seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system, 593 trace_event_name(&tu->tp.call), tu->filename, 594 (int)(sizeof(void *) * 2), tu->offset); 595 596 if (tu->ref_ctr_offset) 597 seq_printf(m, "(0x%lx)", tu->ref_ctr_offset); 598 599 for (i = 0; i < tu->tp.nr_args; i++) 600 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); 601 602 seq_putc(m, '\n'); 603 return 0; 604 } 605 606 static int probes_seq_show(struct seq_file *m, void *v) 607 { 608 struct dyn_event *ev = v; 609 610 if (!is_trace_uprobe(ev)) 611 return 0; 612 613 return trace_uprobe_show(m, ev); 614 } 615 616 static const struct seq_operations probes_seq_op = { 617 .start = dyn_event_seq_start, 618 .next = dyn_event_seq_next, 619 .stop = dyn_event_seq_stop, 620 .show = probes_seq_show 621 }; 622 623 static int probes_open(struct inode *inode, struct file *file) 624 { 625 int ret; 626 627 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 628 ret = dyn_events_release_all(&trace_uprobe_ops); 629 if (ret) 630 return ret; 631 } 632 633 return seq_open(file, &probes_seq_op); 634 } 635 636 static ssize_t probes_write(struct file *file, const char __user *buffer, 637 size_t count, loff_t *ppos) 638 { 639 return trace_parse_run_command(file, buffer, count, ppos, 640 create_or_delete_trace_uprobe); 641 } 642 643 static const struct file_operations uprobe_events_ops = { 644 .owner = THIS_MODULE, 645 .open = probes_open, 646 .read = seq_read, 647 .llseek = seq_lseek, 648 .release = seq_release, 649 .write = probes_write, 650 }; 651 652 /* Probes profiling interfaces */ 653 static int probes_profile_seq_show(struct seq_file *m, void *v) 654 { 655 struct dyn_event *ev = v; 656 struct trace_uprobe *tu; 657 658 if (!is_trace_uprobe(ev)) 659 return 0; 660 661 tu = to_trace_uprobe(ev); 662 seq_printf(m, " %s %-44s %15lu\n", tu->filename, 663 trace_event_name(&tu->tp.call), tu->nhit); 664 return 0; 665 } 666 667 static const struct seq_operations profile_seq_op = { 668 .start = dyn_event_seq_start, 669 .next = dyn_event_seq_next, 670 .stop = dyn_event_seq_stop, 671 .show = probes_profile_seq_show 672 }; 673 674 static int profile_open(struct inode *inode, struct file *file) 675 { 676 return seq_open(file, &profile_seq_op); 677 } 678 679 static const struct file_operations uprobe_profile_ops = { 680 .owner = THIS_MODULE, 681 .open = profile_open, 682 .read = seq_read, 683 .llseek = seq_lseek, 684 .release = seq_release, 685 }; 686 687 struct uprobe_cpu_buffer { 688 struct mutex mutex; 689 void *buf; 690 }; 691 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; 692 static int uprobe_buffer_refcnt; 693 694 static int uprobe_buffer_init(void) 695 { 696 int cpu, err_cpu; 697 698 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); 699 if (uprobe_cpu_buffer == NULL) 700 return -ENOMEM; 701 702 for_each_possible_cpu(cpu) { 703 struct page *p = alloc_pages_node(cpu_to_node(cpu), 704 GFP_KERNEL, 0); 705 if (p == NULL) { 706 err_cpu = cpu; 707 goto err; 708 } 709 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); 710 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); 711 } 712 713 return 0; 714 715 err: 716 for_each_possible_cpu(cpu) { 717 if (cpu == err_cpu) 718 break; 719 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); 720 } 721 722 free_percpu(uprobe_cpu_buffer); 723 return -ENOMEM; 724 } 725 726 static int uprobe_buffer_enable(void) 727 { 728 int ret = 0; 729 730 BUG_ON(!mutex_is_locked(&event_mutex)); 731 732 if (uprobe_buffer_refcnt++ == 0) { 733 ret = uprobe_buffer_init(); 734 if (ret < 0) 735 uprobe_buffer_refcnt--; 736 } 737 738 return ret; 739 } 740 741 static void uprobe_buffer_disable(void) 742 { 743 int cpu; 744 745 BUG_ON(!mutex_is_locked(&event_mutex)); 746 747 if (--uprobe_buffer_refcnt == 0) { 748 for_each_possible_cpu(cpu) 749 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, 750 cpu)->buf); 751 752 free_percpu(uprobe_cpu_buffer); 753 uprobe_cpu_buffer = NULL; 754 } 755 } 756 757 static struct uprobe_cpu_buffer *uprobe_buffer_get(void) 758 { 759 struct uprobe_cpu_buffer *ucb; 760 int cpu; 761 762 cpu = raw_smp_processor_id(); 763 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); 764 765 /* 766 * Use per-cpu buffers for fastest access, but we might migrate 767 * so the mutex makes sure we have sole access to it. 768 */ 769 mutex_lock(&ucb->mutex); 770 771 return ucb; 772 } 773 774 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) 775 { 776 mutex_unlock(&ucb->mutex); 777 } 778 779 static void __uprobe_trace_func(struct trace_uprobe *tu, 780 unsigned long func, struct pt_regs *regs, 781 struct uprobe_cpu_buffer *ucb, int dsize, 782 struct trace_event_file *trace_file) 783 { 784 struct uprobe_trace_entry_head *entry; 785 struct ring_buffer_event *event; 786 struct ring_buffer *buffer; 787 void *data; 788 int size, esize; 789 struct trace_event_call *call = &tu->tp.call; 790 791 WARN_ON(call != trace_file->event_call); 792 793 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) 794 return; 795 796 if (trace_trigger_soft_disabled(trace_file)) 797 return; 798 799 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 800 size = esize + tu->tp.size + dsize; 801 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 802 call->event.type, size, 0, 0); 803 if (!event) 804 return; 805 806 entry = ring_buffer_event_data(event); 807 if (is_ret_probe(tu)) { 808 entry->vaddr[0] = func; 809 entry->vaddr[1] = instruction_pointer(regs); 810 data = DATAOF_TRACE_ENTRY(entry, true); 811 } else { 812 entry->vaddr[0] = instruction_pointer(regs); 813 data = DATAOF_TRACE_ENTRY(entry, false); 814 } 815 816 memcpy(data, ucb->buf, tu->tp.size + dsize); 817 818 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0); 819 } 820 821 /* uprobe handler */ 822 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, 823 struct uprobe_cpu_buffer *ucb, int dsize) 824 { 825 struct event_file_link *link; 826 827 if (is_ret_probe(tu)) 828 return 0; 829 830 rcu_read_lock(); 831 list_for_each_entry_rcu(link, &tu->tp.files, list) 832 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); 833 rcu_read_unlock(); 834 835 return 0; 836 } 837 838 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 839 struct pt_regs *regs, 840 struct uprobe_cpu_buffer *ucb, int dsize) 841 { 842 struct event_file_link *link; 843 844 rcu_read_lock(); 845 list_for_each_entry_rcu(link, &tu->tp.files, list) 846 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); 847 rcu_read_unlock(); 848 } 849 850 /* Event entry printers */ 851 static enum print_line_t 852 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) 853 { 854 struct uprobe_trace_entry_head *entry; 855 struct trace_seq *s = &iter->seq; 856 struct trace_uprobe *tu; 857 u8 *data; 858 859 entry = (struct uprobe_trace_entry_head *)iter->ent; 860 tu = container_of(event, struct trace_uprobe, tp.call.event); 861 862 if (is_ret_probe(tu)) { 863 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", 864 trace_event_name(&tu->tp.call), 865 entry->vaddr[1], entry->vaddr[0]); 866 data = DATAOF_TRACE_ENTRY(entry, true); 867 } else { 868 trace_seq_printf(s, "%s: (0x%lx)", 869 trace_event_name(&tu->tp.call), 870 entry->vaddr[0]); 871 data = DATAOF_TRACE_ENTRY(entry, false); 872 } 873 874 if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0) 875 goto out; 876 877 trace_seq_putc(s, '\n'); 878 879 out: 880 return trace_handle_return(s); 881 } 882 883 typedef bool (*filter_func_t)(struct uprobe_consumer *self, 884 enum uprobe_filter_ctx ctx, 885 struct mm_struct *mm); 886 887 static int 888 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file, 889 filter_func_t filter) 890 { 891 bool enabled = trace_probe_is_enabled(&tu->tp); 892 struct event_file_link *link = NULL; 893 int ret; 894 895 if (file) { 896 if (tu->tp.flags & TP_FLAG_PROFILE) 897 return -EINTR; 898 899 link = kmalloc(sizeof(*link), GFP_KERNEL); 900 if (!link) 901 return -ENOMEM; 902 903 link->file = file; 904 list_add_tail_rcu(&link->list, &tu->tp.files); 905 906 tu->tp.flags |= TP_FLAG_TRACE; 907 } else { 908 if (tu->tp.flags & TP_FLAG_TRACE) 909 return -EINTR; 910 911 tu->tp.flags |= TP_FLAG_PROFILE; 912 } 913 914 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 915 916 if (enabled) 917 return 0; 918 919 ret = uprobe_buffer_enable(); 920 if (ret) 921 goto err_flags; 922 923 tu->consumer.filter = filter; 924 tu->inode = d_real_inode(tu->path.dentry); 925 if (tu->ref_ctr_offset) { 926 ret = uprobe_register_refctr(tu->inode, tu->offset, 927 tu->ref_ctr_offset, &tu->consumer); 928 } else { 929 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); 930 } 931 932 if (ret) 933 goto err_buffer; 934 935 return 0; 936 937 err_buffer: 938 uprobe_buffer_disable(); 939 940 err_flags: 941 if (file) { 942 list_del(&link->list); 943 kfree(link); 944 tu->tp.flags &= ~TP_FLAG_TRACE; 945 } else { 946 tu->tp.flags &= ~TP_FLAG_PROFILE; 947 } 948 return ret; 949 } 950 951 static void 952 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file) 953 { 954 if (!trace_probe_is_enabled(&tu->tp)) 955 return; 956 957 if (file) { 958 struct event_file_link *link; 959 960 link = find_event_file_link(&tu->tp, file); 961 if (!link) 962 return; 963 964 list_del_rcu(&link->list); 965 /* synchronize with u{,ret}probe_trace_func */ 966 synchronize_rcu(); 967 kfree(link); 968 969 if (!list_empty(&tu->tp.files)) 970 return; 971 } 972 973 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 974 975 uprobe_unregister(tu->inode, tu->offset, &tu->consumer); 976 tu->inode = NULL; 977 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; 978 979 uprobe_buffer_disable(); 980 } 981 982 static int uprobe_event_define_fields(struct trace_event_call *event_call) 983 { 984 int ret, size; 985 struct uprobe_trace_entry_head field; 986 struct trace_uprobe *tu = event_call->data; 987 988 if (is_ret_probe(tu)) { 989 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); 990 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); 991 size = SIZEOF_TRACE_ENTRY(true); 992 } else { 993 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); 994 size = SIZEOF_TRACE_ENTRY(false); 995 } 996 997 return traceprobe_define_arg_fields(event_call, size, &tu->tp); 998 } 999 1000 #ifdef CONFIG_PERF_EVENTS 1001 static bool 1002 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) 1003 { 1004 struct perf_event *event; 1005 1006 if (filter->nr_systemwide) 1007 return true; 1008 1009 list_for_each_entry(event, &filter->perf_events, hw.tp_list) { 1010 if (event->hw.target->mm == mm) 1011 return true; 1012 } 1013 1014 return false; 1015 } 1016 1017 static inline bool 1018 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) 1019 { 1020 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); 1021 } 1022 1023 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) 1024 { 1025 bool done; 1026 1027 write_lock(&tu->filter.rwlock); 1028 if (event->hw.target) { 1029 list_del(&event->hw.tp_list); 1030 done = tu->filter.nr_systemwide || 1031 (event->hw.target->flags & PF_EXITING) || 1032 uprobe_filter_event(tu, event); 1033 } else { 1034 tu->filter.nr_systemwide--; 1035 done = tu->filter.nr_systemwide; 1036 } 1037 write_unlock(&tu->filter.rwlock); 1038 1039 if (!done) 1040 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); 1041 1042 return 0; 1043 } 1044 1045 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) 1046 { 1047 bool done; 1048 int err; 1049 1050 write_lock(&tu->filter.rwlock); 1051 if (event->hw.target) { 1052 /* 1053 * event->parent != NULL means copy_process(), we can avoid 1054 * uprobe_apply(). current->mm must be probed and we can rely 1055 * on dup_mmap() which preserves the already installed bp's. 1056 * 1057 * attr.enable_on_exec means that exec/mmap will install the 1058 * breakpoints we need. 1059 */ 1060 done = tu->filter.nr_systemwide || 1061 event->parent || event->attr.enable_on_exec || 1062 uprobe_filter_event(tu, event); 1063 list_add(&event->hw.tp_list, &tu->filter.perf_events); 1064 } else { 1065 done = tu->filter.nr_systemwide; 1066 tu->filter.nr_systemwide++; 1067 } 1068 write_unlock(&tu->filter.rwlock); 1069 1070 err = 0; 1071 if (!done) { 1072 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); 1073 if (err) 1074 uprobe_perf_close(tu, event); 1075 } 1076 return err; 1077 } 1078 1079 static bool uprobe_perf_filter(struct uprobe_consumer *uc, 1080 enum uprobe_filter_ctx ctx, struct mm_struct *mm) 1081 { 1082 struct trace_uprobe *tu; 1083 int ret; 1084 1085 tu = container_of(uc, struct trace_uprobe, consumer); 1086 read_lock(&tu->filter.rwlock); 1087 ret = __uprobe_perf_filter(&tu->filter, mm); 1088 read_unlock(&tu->filter.rwlock); 1089 1090 return ret; 1091 } 1092 1093 static void __uprobe_perf_func(struct trace_uprobe *tu, 1094 unsigned long func, struct pt_regs *regs, 1095 struct uprobe_cpu_buffer *ucb, int dsize) 1096 { 1097 struct trace_event_call *call = &tu->tp.call; 1098 struct uprobe_trace_entry_head *entry; 1099 struct hlist_head *head; 1100 void *data; 1101 int size, esize; 1102 int rctx; 1103 1104 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1105 return; 1106 1107 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1108 1109 size = esize + tu->tp.size + dsize; 1110 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); 1111 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) 1112 return; 1113 1114 preempt_disable(); 1115 head = this_cpu_ptr(call->perf_events); 1116 if (hlist_empty(head)) 1117 goto out; 1118 1119 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1120 if (!entry) 1121 goto out; 1122 1123 if (is_ret_probe(tu)) { 1124 entry->vaddr[0] = func; 1125 entry->vaddr[1] = instruction_pointer(regs); 1126 data = DATAOF_TRACE_ENTRY(entry, true); 1127 } else { 1128 entry->vaddr[0] = instruction_pointer(regs); 1129 data = DATAOF_TRACE_ENTRY(entry, false); 1130 } 1131 1132 memcpy(data, ucb->buf, tu->tp.size + dsize); 1133 1134 if (size - esize > tu->tp.size + dsize) { 1135 int len = tu->tp.size + dsize; 1136 1137 memset(data + len, 0, size - esize - len); 1138 } 1139 1140 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1141 head, NULL); 1142 out: 1143 preempt_enable(); 1144 } 1145 1146 /* uprobe profile handler */ 1147 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, 1148 struct uprobe_cpu_buffer *ucb, int dsize) 1149 { 1150 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) 1151 return UPROBE_HANDLER_REMOVE; 1152 1153 if (!is_ret_probe(tu)) 1154 __uprobe_perf_func(tu, 0, regs, ucb, dsize); 1155 return 0; 1156 } 1157 1158 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 1159 struct pt_regs *regs, 1160 struct uprobe_cpu_buffer *ucb, int dsize) 1161 { 1162 __uprobe_perf_func(tu, func, regs, ucb, dsize); 1163 } 1164 1165 int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type, 1166 const char **filename, u64 *probe_offset, 1167 bool perf_type_tracepoint) 1168 { 1169 const char *pevent = trace_event_name(event->tp_event); 1170 const char *group = event->tp_event->class->system; 1171 struct trace_uprobe *tu; 1172 1173 if (perf_type_tracepoint) 1174 tu = find_probe_event(pevent, group); 1175 else 1176 tu = event->tp_event->data; 1177 if (!tu) 1178 return -EINVAL; 1179 1180 *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE 1181 : BPF_FD_TYPE_UPROBE; 1182 *filename = tu->filename; 1183 *probe_offset = tu->offset; 1184 return 0; 1185 } 1186 #endif /* CONFIG_PERF_EVENTS */ 1187 1188 static int 1189 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type, 1190 void *data) 1191 { 1192 struct trace_uprobe *tu = event->data; 1193 struct trace_event_file *file = data; 1194 1195 switch (type) { 1196 case TRACE_REG_REGISTER: 1197 return probe_event_enable(tu, file, NULL); 1198 1199 case TRACE_REG_UNREGISTER: 1200 probe_event_disable(tu, file); 1201 return 0; 1202 1203 #ifdef CONFIG_PERF_EVENTS 1204 case TRACE_REG_PERF_REGISTER: 1205 return probe_event_enable(tu, NULL, uprobe_perf_filter); 1206 1207 case TRACE_REG_PERF_UNREGISTER: 1208 probe_event_disable(tu, NULL); 1209 return 0; 1210 1211 case TRACE_REG_PERF_OPEN: 1212 return uprobe_perf_open(tu, data); 1213 1214 case TRACE_REG_PERF_CLOSE: 1215 return uprobe_perf_close(tu, data); 1216 1217 #endif 1218 default: 1219 return 0; 1220 } 1221 return 0; 1222 } 1223 1224 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) 1225 { 1226 struct trace_uprobe *tu; 1227 struct uprobe_dispatch_data udd; 1228 struct uprobe_cpu_buffer *ucb; 1229 int dsize, esize; 1230 int ret = 0; 1231 1232 1233 tu = container_of(con, struct trace_uprobe, consumer); 1234 tu->nhit++; 1235 1236 udd.tu = tu; 1237 udd.bp_addr = instruction_pointer(regs); 1238 1239 current->utask->vaddr = (unsigned long) &udd; 1240 1241 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1242 return 0; 1243 1244 dsize = __get_data_size(&tu->tp, regs); 1245 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1246 1247 ucb = uprobe_buffer_get(); 1248 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); 1249 1250 if (tu->tp.flags & TP_FLAG_TRACE) 1251 ret |= uprobe_trace_func(tu, regs, ucb, dsize); 1252 1253 #ifdef CONFIG_PERF_EVENTS 1254 if (tu->tp.flags & TP_FLAG_PROFILE) 1255 ret |= uprobe_perf_func(tu, regs, ucb, dsize); 1256 #endif 1257 uprobe_buffer_put(ucb); 1258 return ret; 1259 } 1260 1261 static int uretprobe_dispatcher(struct uprobe_consumer *con, 1262 unsigned long func, struct pt_regs *regs) 1263 { 1264 struct trace_uprobe *tu; 1265 struct uprobe_dispatch_data udd; 1266 struct uprobe_cpu_buffer *ucb; 1267 int dsize, esize; 1268 1269 tu = container_of(con, struct trace_uprobe, consumer); 1270 1271 udd.tu = tu; 1272 udd.bp_addr = func; 1273 1274 current->utask->vaddr = (unsigned long) &udd; 1275 1276 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1277 return 0; 1278 1279 dsize = __get_data_size(&tu->tp, regs); 1280 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1281 1282 ucb = uprobe_buffer_get(); 1283 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); 1284 1285 if (tu->tp.flags & TP_FLAG_TRACE) 1286 uretprobe_trace_func(tu, func, regs, ucb, dsize); 1287 1288 #ifdef CONFIG_PERF_EVENTS 1289 if (tu->tp.flags & TP_FLAG_PROFILE) 1290 uretprobe_perf_func(tu, func, regs, ucb, dsize); 1291 #endif 1292 uprobe_buffer_put(ucb); 1293 return 0; 1294 } 1295 1296 static struct trace_event_functions uprobe_funcs = { 1297 .trace = print_uprobe_event 1298 }; 1299 1300 static inline void init_trace_event_call(struct trace_uprobe *tu, 1301 struct trace_event_call *call) 1302 { 1303 INIT_LIST_HEAD(&call->class->fields); 1304 call->event.funcs = &uprobe_funcs; 1305 call->class->define_fields = uprobe_event_define_fields; 1306 1307 call->flags = TRACE_EVENT_FL_UPROBE; 1308 call->class->reg = trace_uprobe_register; 1309 call->data = tu; 1310 } 1311 1312 static int register_uprobe_event(struct trace_uprobe *tu) 1313 { 1314 struct trace_event_call *call = &tu->tp.call; 1315 int ret = 0; 1316 1317 init_trace_event_call(tu, call); 1318 1319 if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) 1320 return -ENOMEM; 1321 1322 ret = register_trace_event(&call->event); 1323 if (!ret) { 1324 kfree(call->print_fmt); 1325 return -ENODEV; 1326 } 1327 1328 ret = trace_add_event_call(call); 1329 1330 if (ret) { 1331 pr_info("Failed to register uprobe event: %s\n", 1332 trace_event_name(call)); 1333 kfree(call->print_fmt); 1334 unregister_trace_event(&call->event); 1335 } 1336 1337 return ret; 1338 } 1339 1340 static int unregister_uprobe_event(struct trace_uprobe *tu) 1341 { 1342 int ret; 1343 1344 /* tu->event is unregistered in trace_remove_event_call() */ 1345 ret = trace_remove_event_call(&tu->tp.call); 1346 if (ret) 1347 return ret; 1348 kfree(tu->tp.call.print_fmt); 1349 tu->tp.call.print_fmt = NULL; 1350 return 0; 1351 } 1352 1353 #ifdef CONFIG_PERF_EVENTS 1354 struct trace_event_call * 1355 create_local_trace_uprobe(char *name, unsigned long offs, 1356 unsigned long ref_ctr_offset, bool is_return) 1357 { 1358 struct trace_uprobe *tu; 1359 struct path path; 1360 int ret; 1361 1362 ret = kern_path(name, LOOKUP_FOLLOW, &path); 1363 if (ret) 1364 return ERR_PTR(ret); 1365 1366 if (!d_is_reg(path.dentry)) { 1367 path_put(&path); 1368 return ERR_PTR(-EINVAL); 1369 } 1370 1371 /* 1372 * local trace_kprobes are not added to dyn_event, so they are never 1373 * searched in find_trace_kprobe(). Therefore, there is no concern of 1374 * duplicated name "DUMMY_EVENT" here. 1375 */ 1376 tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0, 1377 is_return); 1378 1379 if (IS_ERR(tu)) { 1380 pr_info("Failed to allocate trace_uprobe.(%d)\n", 1381 (int)PTR_ERR(tu)); 1382 path_put(&path); 1383 return ERR_CAST(tu); 1384 } 1385 1386 tu->offset = offs; 1387 tu->path = path; 1388 tu->ref_ctr_offset = ref_ctr_offset; 1389 tu->filename = kstrdup(name, GFP_KERNEL); 1390 init_trace_event_call(tu, &tu->tp.call); 1391 1392 if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) { 1393 ret = -ENOMEM; 1394 goto error; 1395 } 1396 1397 return &tu->tp.call; 1398 error: 1399 free_trace_uprobe(tu); 1400 return ERR_PTR(ret); 1401 } 1402 1403 void destroy_local_trace_uprobe(struct trace_event_call *event_call) 1404 { 1405 struct trace_uprobe *tu; 1406 1407 tu = container_of(event_call, struct trace_uprobe, tp.call); 1408 1409 kfree(tu->tp.call.print_fmt); 1410 tu->tp.call.print_fmt = NULL; 1411 1412 free_trace_uprobe(tu); 1413 } 1414 #endif /* CONFIG_PERF_EVENTS */ 1415 1416 /* Make a trace interface for controling probe points */ 1417 static __init int init_uprobe_trace(void) 1418 { 1419 struct dentry *d_tracer; 1420 int ret; 1421 1422 ret = dyn_event_register(&trace_uprobe_ops); 1423 if (ret) 1424 return ret; 1425 1426 d_tracer = tracing_init_dentry(); 1427 if (IS_ERR(d_tracer)) 1428 return 0; 1429 1430 trace_create_file("uprobe_events", 0644, d_tracer, 1431 NULL, &uprobe_events_ops); 1432 /* Profile interface */ 1433 trace_create_file("uprobe_profile", 0444, d_tracer, 1434 NULL, &uprobe_profile_ops); 1435 return 0; 1436 } 1437 1438 fs_initcall(init_uprobe_trace); 1439